Clasp and apparatus for molding same



p 1968 s. DE WOSKIN 3,402,441

CLASP AND APPARATUS FOR MOLDING SAME Filed Nov. 2, 1967 United States Patent 3,402,441 CLASP AND APPARATUS FOR MOLDING SAME Irvin S. De Woskin, St. Louis, Mo., assignor to Beltx Corporation, St. Louis, Mo., a corporation of Missouri Filed Nov. 2, 1967, Ser. No. 680,171 8 Claims. (Cl. 24-245) ABSTRACT OF THE DISCLOSURE A clasp of plastic material has a hinge line intermediate its ends so that body and tongue portions thereof may be placed in face-to-face relation by folding along the hinge line. The body has an opening therein with a first portion towards one end of the body, a second and smaller portion towards the other end of the body and a constricted neck between the portions. The tongue has transverse and longitudinal slots at one end thereof, and a stem integrally hinged to the tongue adjacent the end of the longitudinal slot. A button is provided on the end of the stem. The length of the stem corresponds to the length of the longitudinal slot and the width and thickness of the button are less than the length and width of the transverse slot. The first portion of the body opening is larger than the button, the second portion is smaller than the button but wider than the stern, and the neck is narrower than the stem. Apparatus for molding the clasp includes a pair of dies having flat mating faces, one of the dies having a cavity shaped for molding the body and tongue portions and the other die having a cavity shaped for molding the body portion. An island extends up from the bottom of the tongue cavity at one end thereof, the island extending transversely with respect to the tongue cavity and having a cavity therein for molding half of the button. A channel extends between the tongue and button cavities for molding the stem. The other die has a cavity in its mating face registering with the button cavity for molding the other half of the button.

Background of the invention the purpose, they have not proven entirely satisfactory in that they are relatively expensive to produce and the metal or wire portions have to be protected, as by coating, against corrosion. Such coatings are not entirely effective in that they frequently chip or peel and expose the underlying metal, particularly when subjected to repeated laundering, thereby destroying the protective function of the coating and detracting from the appearance of the clasp.

In addition, such metal and fabric clasps are obtrusive and uncomfortable when worn under an outer garment. Although attempts have been made to employ plastics in fabricating such clasps, such attempts have not been fully successful in that the clasps, and particularly the button portions thereof, have been difiicult to integrally mold. Thus, the configurations of such prior art plastic clasps are generally such that they are difiicult to manipulate for interlocking and releasing of their parts.

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Summary of the invention Among the several objects of the present invention may be noted the provision of a clasp for apparel or the like made of plastic or other flexible material which is easily manipulated for interlocking and releasing of its parts; the provision of such a clasp having its parts arranged so that inadvertent release of interlocking portions thereof is prevented; the provision of a clasp of the class described which is adapted to be worn under an outer garment and which is relatively flat and unobtrusive when so worn; the provision of apparatus for integrally molding a clasp of the class described; the provision of such apparatus for molding the clasp with an integral button on one of its portions, which button is adapted to be moved from a first position for molding to a second position for use; and the provision of such a clasp and apparatus which are characterized by simplicity of construction and low cost. Other objects and feature-s will be in part apparent and in part pointed out hereinafter.

A plastic clasp of this invention comprises an elongate body having an opening therein, the opening having a first portion toward one end of the body and a second and smaller portion toward the other end of the body with a constricted neck between the portions. A tongue is associated with the body, the tongue having a transverse slot adjacent one end and a longitudinal slot extending from the transverse slot. A stem is integrally hinged to the tongue at the end of the longitudinal slot and a button is provided on the stem transverse to the stem. The stem has a length corresponding to the length of the longitudinal slot and the button has a width less than the length of the transverse slot and a thickness less than the width of the transverse slot. The first portion of the opening in the body is larger than the button and the second portion is smaller than the button but wider than the stem. The neck in the body is narrower than the stern for entry of the button in the first portion and snapping of the stem through the neck into the second portion. Apparatus for molding the plastic clasp comprises a pair of mating dies having flat mating faces, one of the dies having in the mating face thereof an elongate cavity shaped for molding the tongue. An island is provided on the die extending up from the bottom of the tongue cavity adjacent its end and having its end face flush with the mating face of the die, the island extending transversely with respect to the cavity. A cavity is provided in the island for molding half of the button, and a channel extends between the tongue cavity and the button cavity for molding the stem. The second die has a cavity in its mating face registering with the button cavity for molding the other half of the button. The stem is adapted to be bent away from the tongue after removal of the tongue from the dies.

Brief description of the drawing FIG. 1 and 2 are plan views of the two dies of a mold used for molding the clasp of this invention;

FIG. 3 is an enlarged vertical section of the dies assembled with their mating faces in registry;

FIG. 4 is a fragmentary section on line 44 of FIG. 3;

FIG. 5 is a front view of the clasp in an initial fiat condition as removed from the mold;

FIG. 6 is a side elevation of the clasp showing it folded;

FIG. 7 is a front view of the clasp with parts interlocked; and

'FIG. 8 is a side elevation of the clasp gripping an article of apparel.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawtugs.

Description of the preferred embodiment Referring now to the drawings, a clasp 1 of this invention is shown in FIGS. -8 to comprise an elongate flat strip of flexible plastic material. At the center of the clasp are two head portions designated 3 and 5 integrally hinged together on a transverse hinge line 7. The clasp may be conveniently molded in one piece, as will be set forth more fully hereinafter, and the hinge line 7 may be of reduced thickness to increase the flexibility thereof.

Head portions 3 and 5 have transverse slots 9 and 11, respectively, which are located so that they are placed in registry with each other when the clasp is folded along hinge line 7. Slots 9 and 11 provide means for attachment of the clasp to a supporter, such as illustrated in phantom at 13 in FIGS. 6 and 7. Slots 9 and 11 may be joined by a longitudinal slot (not shown) to provide means for conveniently passing the supporter 13 into the slots.

An elongate flexible tongue 15 integral with head portion 3 extends lengthwise of the clasp from the edge of head portion 3 opposite head portion 5. Tongue 15 has a tab 17 at its free end, and transverse and longitudinal slots 19 and 21, respectively, therein. A stem 23 is integrally hinged to the tongue 15 at the end of longitudinal slot 21 towards head portion 3, and a circular disk-shaped button is integrally formed on the end of stem 23, the button lying in a plane transverse to the plane of the stem. Stem 23 has a length corresponding to the length of longitudinal slot 21 and button 25 has a width or diameter less than the length of transverse slot 19 and a thickness less than the width of transverse slot 19. Thus, button 25 and stem 23 are respectively positionable in slots 19 and 21, such as shown in FIG, 5, but are adapted to be bent away fro-m the tongue after molding so that button 25 and stem 23 are respectively parallel and transverse to the plane of tongue 15, such as shown in FIG. 6. An elongate flat body 27 extends lengthwise of the clasp from the edge of head portion 5 opposite its connection to head portion 3. Body 25 has an elongate generally keyhole-shaped opening 29 extending lengthwise of the clasp from the head portion 5 to substantially the free end of the body. The end portion of opening 29 adjacent head 5 is designated 29a. This portion of the opening is slightly larger than the diameter of button 25 so that the button may pass through it with the plane of the button parallel to the plane of the body. At the other end of opening 29 is a smaller portion designated 29b which is narrower than the diameter of button 25 but wider than stem 23. Between portions 29a and 29b is a constricted neck portion 290 which is slightly narrower than stem 23 for entry of the button in the first portion 29a and snapping of the stem through the neck into the second portion 29b. Neck portion 290 is formed by rounded reduced-thickness projections 31 extending inwardly into opening 29 from opposite sides thereof.

As set forth above, the clasp is formed of a flexible plastic material. It is preferred that the entire clasp be integrally molded in one piece, as by injection molding of polypropylene. It has been found that polypropylene has the characteristic of being flexible at an integral reduced thickness hinge, while, at the same time, being remarkably strong. It even appears that the strength of the material increases with repeated flexing at the hinge. If desired, the clasp may be formed in two pieces for connecting the ends of a strap such as found on a brassiere, for example.

To use the clasp, the tongue 15 and body 27 are folded on hinge line 7 until they are generally in face-to-face relation. They are suitably secured to a supporter 13 and are placed over a stocking S (FIG. 8), for example, with the tongue and body straddling the top of the stocking. Tongue 15 is then bent into an arc to place button 25 in registry with portion 29a of opening 29 in body 27. Button 25 is thus in a plane generally parallel to body 27 and a portion of stocking S is stretched across opening 29a, Button 25 is then pushed through portion 29a forcing a portion of the stocking through the buttonhole with it. The button is next moved downwardly to its FIG. 7 position With stem 23 passing through constricted neck portion 290 and into portion 29b. Since neck portion 29c is narrower than the width of stem 23, movement of the stem through the neck requires the application of a positive force to snap the stem through the neck. Inadvertent removal of the stocking from the button is prevented since opening 291) is smaller than the diameter of button 25, while inadvertent removal of the stocking from the clasp by lifting the button 25 and passing it through portion 29a of the opening is prevented by the constricted neck portion 290.

To release stocking S, button 25 is moved upwardly (or body 27 downwardly) until the button is in line with portion 29a of the opening in the body. The button is then moved to its FIG. 6 position where the stocking is released.

Referring to FIGS. l-4, a pair of mating dies are indicated at 33 and 35 for molding the clasp by injection molding. The dies 33 and 35 have mating planar die faces 37 and 38. At the center of die 33 is a pair of generally oval cavities 39 and 41 shaped for molding one-half the thickness of each of the head portions 3 and 5. The oval cavities are interconnected by a shallow rectangular cavity 43 shaped for molding the reduced-thickness hinge line 7. Oval cavity 39 has an elongate tongue cavity 45 extending from its side opposite the hinge cavity and oval cavity 41 has an elongate body cavity 47 extending from its side opposite the hinge cavity. The tongue cavity 45 has an end cavity 49 with a raised transversely extending island 51 therein. The island is of generally oval configuration having a pair 'of spaced longitudinally extending raised portions 53 at one side thereof. Island 51 defines a semicircular cavity 55 (FIGS. 3 and 4) shaped for molding half of the button 25, and portions 53 define a channel 57 extending from tongue cavity 45 to button cavity 55 for molding the stem 23 and filling the button cavity. The island 51 extends up from the bottom of cavity 45 and has its end face flush with face 37 of die 33.

The body cavity 47 has a raised island 59 in its center with its end face flush with the face 37 of die 33. The island 59 is shaped to form opening 29 in body 27 of the clasp. A pair of similar islands 61 and 63 are provided at the centers of cavities 39 and 41 for respectively fortning slots 9 and 11 in head portions 3 and 5 of the clasp. Die 33 is provided with guide pins, such as indicated at 65, and die 35 with a corresponding pair of apertures 67 for guiding the dies into registry when brought together. A pair of threaded apertures 69 are also provided in die 33 for receiving threaded bolts (not shown) extending through a mating pair of countersunk apertures 71 in die 35 to clamp the dies together. Other arrangements may, of course, be provided for guiding and clamping the dies in face-to-face registry.

The die 35 has a pair of spaced oval cavities 73 and 75 shaped for molding the other half of head portions 3 and 5 and a body cavity 77 shaped for molding the other half of body 27. Body cavity 77 has a center island 79 and oval cavities 73 and 75 have islands 81 and 83. At the end of die 35 opposite body cavity 77 is a semicircular cavity 85 shaped for molding the other half of button 25 and a channel 87 extending into the button cavity for filling the same.

A sprue 89 and a pair of runners 91 are provided in the mating die for entry of the molten plastic into the mold cavities.

To mold the clasp of FIGS. 5-8 in the dies of FIGS. l-4, mating dies 33 and 35 are clamped together in faceto-face contacting relationship and a molten plastic, such as polypropylene, is injected into the sprue 89 and runners 91 for entry into the mold cavities at ovals 39, 73 and 41, 75. Thus, body cavities 47 and 77 cooperate to mold the opposite sides of the body of the clasp, with cavity 77 providing the half thickness constricted neck portion 29c. The cavities 39, 73 and 41, 75 mold the head portions of the clasp and the interconnecting cavity 43 molds the reduced thickness hinge line 7. The tongue and end tab of the clasp are molded in the cavities 45 and 49, and the transverse and longitudinal slots are formed by raised islands 51 and 53, respectively. Channel 57 in die 33 integrally molds the stem of the clasp at the end of the tongue adjacent the longitudinal slot and cavities 55 and 85 mold the button halves. Thus, as illustrated in FIG. 5, when the clasp is stripped or removed from the dies the button is positioned transverse to the tongue in slot 19 and the stem is coplanar with the tongue in slot 21. As set forth above, however, to use the clasp stem 23 is bent outwardly so that button 25 lies in a plane parallel to the plane of tongue .15.

In View of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the in vention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A clasp formed of plastic material comprising:

an elongate body having an opening therein, said opening having a first portion toward one end of the body and a second smaller portion toward the other end of the body with a constricted neck between said portions,

a tongue associated with said body, said tongue having a transverse slot adjacent one end and a longitudinal slot extending from said transverse slot, a stem integrally hinged to the tongue at the end of said longitudinal slot, and a button on said stern transverse to said stem, the stem having a length corresponding to the length of the longitudinal slot and the button having a width less than the length of the transverse slot and a thickness less than the width of the transverse slot,

said first portion of said opening in the body being larger than the button, said second portion being smaller than the butt-on but wider than said stem, and said neck being narrower than said stem for entry of the button in the first portion, and snapping of the stem through the neck into said second portion.

2. A clasp as set forth in claim 1 wherein the body is integrally joined to the tongue along a flexible hinge line, the clasp being foldable on said hinge line so that the body and tongue lie in face-to-face relation when the clasp is in its folded condition.

3. A clasp as set forth in claim 2 further comprising a pair of head portions each having a transverse slot therein, the "slots registering when the clasp is folded for reception of a supporter.

4. A clasp as set forth in claim 1 wherein said longitudinal slot extends from the side of the transverse slot opposite said one end of the tongue.

5. A clasp as set forth in claim 1 wherein said button is disk-shaped and said button and. stem are movable from a first position wherein the button is transverse to the tongue in the transverse slot and the stem is coplanar with the tongue in the longitudinal slot to a second position wherein the button is parallel to the tongue and the stem is transverse to the tongue.

6. Apparatus for molding a plastic clasp having a tongue, said tongue having a transverse slot adjacent one end, there being a longitudinal slot extending from said transverse slot, a stem integrally hinged to the tongue at one end of said longitudinal slot, and a button on said stern transverse to said stem, said apparatus comprising a pair of mating dies having flat mating faces, one of said dies having in the mating face thereof an elongate cavity shaped for molding the tongue, an island on said one die extending up from the bottom of the tongue cavity adjacent one end thereof and having its end face flush with said mating face of said one die, said island extending transversely with respect to the tongue cavity, said island having a cavity therein shaped for molding half of the button, and there being a channel in said island extending between said tongue cavity and said button cavity for molding said stem, and said second die having a cavity in its mating face registering with said button cavity for molding the other half of the button, said stem being adapted to be bent away from the tongue after removal of the tongue from said dies.

7. Apparatus as set forth in claim 6 wherein said clasp has a body integrally hinged to said tongue along a hinge line, said body having an opening therein with a first portion toward one end of the body, a second and smaller portion toward the other end of the body, and a. constricted neck between the portions, said one die further comprises in the mating face thereof an elongate cavity shaped for molding the body, and a cavity extending between the tongue and body cavities shaped for molding the hinge, said hinge cavity being shallower than said tongue and body cavities.

8. Apparatus as set forth in claim 7 wherein said body cavity in said one die is shaped for molding half of the body and said second die further comprises a cavity in its mating face shaped for molding the other half of the body.

References Cited UNITED STATES PATENTS 3,231,954 2/1966 De Woskin et a1 24-245 3,278,152 10/1966 Miller et al. 1844 DQNALD A. GRIFFIN, Primary Examiner. 

